Tommy DeVito: The temperament that pulled the trigger

There is a scene that defines Tommy DeVito: he tells a story, everyone laughs, and suddenly he goes very still — "funny how? funny like a clown? do I amuse you?". For a few seconds nobody knows whether he is going to laugh or kill. That uncertainty is the character: a man whose violence obeys no plan and no benefit, but a temperament with a broken brake. He kills over a joke, over a delay, over a humiliation from years ago. If any criminological theory ever tried to explain people like that — who seem made for crime — it was the theory of the criminal personality.

// The theoryAre there temperaments built for crime?

In 1964, the psychologist Hans Eysenck published Crime and Personality and proposed something bold: criminality is not only poverty or bad company, but rests on personality, and personality has a biological basis. He measured people along three broad dimensions: extraversion (E), neuroticism (N) and, later, psychoticism (P). These are not moral labels: they are inherited ways in which the nervous system reacts. The extravert, he said, has an "under-aroused" brain that constantly seeks stimulation and excitement; the neurotic is unstable and reactive; the psychotic (high P) is cold, impulsive, aggressive and low on empathy.

The key piece is how he ties that to crime. For Eysenck, conscience is not innate: it is learned, like a conditioned reflex. As children we associate "misbehaving" with punishment and fear, and that association, repeated, is internalized until it becomes the voice that holds us back. But conditioning depends on the nervous system — and extraverts, he argued, condition worse: the lesson of punishment does not "catch" in them as easily. The result: whoever combines high E, N and P is more likely never to fully develop that inner brake. It is not that they choose evil; it is that they learned only weakly to fear it.

// The subjectNo brake between impulse and act

What makes Tommy a textbook case — and not just another psychopath — is the disproportion. He does not kill for money or power: he kills for stimulation and for pride, ridiculous triggers for enormous consequences. He shoots a kid who pours him a drink; he beats a "made man" to death over an old slight; his humor and his fury are the same unregulated energy. He is the portrait of Eysenck's high P: cold in the harm, hot in the insult, unable to weigh the cost because the brake that would do the weighing never finished installing. And yet the film does not isolate him: Tommy thrives inside the Mafia, a world that rewards precisely his temperament — a reminder that not even the worst character commits crimes in a vacuum.

// The crackTemperament is not destiny

Eysenck's theory is seductive and, for the most part, did not hold up to the data. The weakest leg is extraversion: studies do not robustly confirm that extraverts commit more crime; of the three dimensions, only psychoticism (P) shows a consistent relationship with antisocial behavior — and "psychoticism" turned out to be a catch-all that overlaps with impulsivity and lack of empathy more than a clean entity. Besides, the theory is reductive: it explains the trigger (temperament) but barely the context (the Mafia that arms Tommy, the subculture that rewards him, the opportunity around him). Modern criminal psychology abandoned the E-N-P model for others — the "big five," self-control — that measure the same thing better without Eysenck's nervous-system machinery.

And there is a shadow worth naming. To say that someone is "born" with a criminal character brushes against the old error of the born criminal: it turns a predisposition into a sentence, and from there to fatalism — "these people never change" — is a short and dangerous step. Eysenck himself, a biologist of behavior, flirted with slippery ground. The honest position is the middle one: temperament exists, it matters and is in part inherited — but correlation is not destiny. Most impulsive, thrill-seeking people never kill anyone; they channel it into a boxing ring, a motorcycle, an emergency room or a boardroom.

That is why Tommy is so frightening on screen: his violence does not look like a decision, it looks like who he is, and that touches a very deep intuition — that there are people "like that," born broken. The theory of the criminal personality forces us to qualify that intuition without denying it outright: yes, temperaments exist and some make everything harder; no, none of them pulls the trigger on its own. Between impulse and act there is a space — the space of the learned brake — and that space can be widened. Tommy never had it. The serious question is not whether he was born with less, but why no one, ever, taught him to fill it.